Re: Landscape lighting bulbs burn out prematurely
- From: Jeff Wisnia <jwisnia@xxxxxxxxxxxxxx>
- Date: Wed, 14 Dec 2005 15:42:52 -0500
"Jeff Wisnia" <jwisnia@xxxxxxxxxxxxxx> wrote in message news:TeSdnXR8cp7b-D3eRVn-gw@xxxxxxxxxxxxxxxxx
: Ike wrote:
: > We have Malibu landscape lighting and the bulbs burn out after only
: > about two months of service. They are very bright compared to my
: > neighbor's Malibu lights and he only replaces bulbs about once a year.
: > When the landscapers installed our lights they did not use the wiring
: > that came with the set. Instead, they used their own wiring which is a
: > much larger gauge resulting in less voltage drop by the time the
: > current reaches the lights. I am sure they thought they were doing me
: > a favor, but their generosity appears to have worked against the life
: > of the bulbs. Is there a simple solution to drop the voltage enough so
: > these bulbs don't burn so hot? Would a standard light dimmer for 120
: > VAC work to adjust the 12 VDC voltage?
: If you happen to have another transformer with a 120 volt primary and a
: 12 or 24 volt secondary lying around you could wire it up as an
: autotransformer to subtract 12 or 24 volts from the 120 volt line and
: use that reduced voltage as the supply voltage to the transformer
: feeding the lights.
: The added transformer's secondary current rating has to be at least as
: large as the primary current the exixting transformer draws of course.
Where the hell did you go to school? There was no course on common sense or safety, was there? Or, umm, more likely you're "self" taught? Keep learning!
: -- : Jeffry Wisnia
: (W1BSV + Brass Rat '57 EE)
: "Truth exists; only falsehood has to be invented."
If you knew anything about college education Pop, you'd recognize that my sig line indicates I'm an MIT electrical engineering grad without my screaming it out. (And FWIW I hold a masters in the same field from an Ivy League school to boot.)
You not even know what an autotransformer is Pop, but I can tell you that back in the '50s I installed at least ten of them ahead of TV sets and expensive home audio equipment to reduce the overly high line voltage present on the lower floors of a high rise apartment building in Cambridge, Taxachusetts. They were wired eggsackly the way I described in my post.
There was a lot of line drop in that building's wiring, and the owners had played with the supply transformer taps so the upper floor's line voltage wouldn't sag too low. That caused the voltage to be up around 135 volts on the lower floors ... The building's manager had a nice little side business going. He was stocking and selling high voltage light bulbs to the tenants on those floors. <G>
That high line voltage raised hell with the filaments in the vacuum tube electronics of that era, just like it appears it might be doing with the OP's light bulbs.
If you think you're right about decrying my advice Pop, let's hear you tell us why you think it's unsafe if done in a workmanlike manner using a transformer with adequate winding insulation ratings.
Otherwise, kindly STFU.
-- Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"Truth exists; only falsehood has to be invented." .
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